A polylactide (or polylactic acid) resin is a kind of a resin including repeating units represented by General Formula below. Unlike existing crude oil-based resins, the polylactide resin is based on biomass, which is usable as a renewable resource, and less discharges CO2 which is a global warming gas, in production, as compared to the existing resins, and has appropriate mechanical strength corresponding to the existing crude oil-based resin, together with eco-friendly characteristics such as biodegradability by moisture and microorganisms when being buried.

The polylactide resin is generally used as disposable packaging/containers, coatings, foamings, films/sheets, fibers, and the like. However, when the polylactide resin, or a copolymer including the same are processed to be a film form and used as a packaging film, and the like, there are disadvantages in that the polylactide resin, or a copolymer including the same is weak against impact and flexibility is deteriorated. In particular, due to deteriorated flexibility, extremely large noise occurs at the time of manufacturing the polylactide resin to be a film form, which has limitation in actual commercialization.
Accordingly, various methods such as adding various components which are possible to provide flexibility to the polylactide resin, mixing the polylactide resin with other resins, and the like, have been considered. However, in the most cases, there are still problems in that the product cost may be largely increased, flexibility may not be sufficiently achieved, and the like. In some cases, transparency, mechanical physical properties, or the like, of the film may be deteriorated.
Therefore, development of the film including the polylactide-based resin capable of exhibiting more improved flexibility while having excellent biodegradability and mechanical physical properties to be usable as a packaging film, and the like, has been continuously demanded.